Which statement correctly describes the NFPA 704 hazard diamond and its color coding?

• A. It indicates health hazards only and ignores other categories.
• B. It indicates flammability, but not health hazards or reactivity.
• C. It indicates health (blue), flammability (red), reactivity/instability (yellow), and special hazards (white); numbers 0–4 indicate severity for each category.
• D. It is used only for labeling household chemicals and has no numeric rating.

Answer: (C)

The NFPA 704 hazard diamond uses four color-coded sections to convey different kinds of danger at a quick glance. Blue stands for health hazards, red for flammability, yellow for reactivity or instability, and white for special hazards. Each section carries a number from 0 to 4 that shows how severe the hazard is in that category, with 0 meaning no hazard and 4 indicating a severe hazard. The white section may also include symbols to flag additional concerns, such as oxidizers or water reactivity. This labeling system is used widely, not just for household products, to communicate multiple hazards at once and guide safety actions.